I picked up the Sears version of a 1977 Atari Heavy Sixer 2600 today and I'm having some problems with it. At first the graphics were hopelessly screwed up and it would drop out if bumped. I cleaned all the contacts, verified I was using a good cartridge and power supply by trying them on my Vader 2600,found out that the transistor by the power switch had cold solder joints and fixed it,and now Pac-Man still looks like this.....help.

The colors are wrong and I can't make out anything resembling what it looks like. The tv is not the issue as I tried it with my Vader 2600 and it works fine. Even tried a different cable and I have the same result.

Image isn't actually rolling,it doesn't move,just looks like that or variations thereof. I can occasionally get sounds but they're not what they should be,just various in game tones. I'll have to take a look at the vader 2600 I have to see if the chips are socketed and if they are I'll try swapping them. Also before anyone suspects the cartridge it does this with multiple games (all of which are fine in the other console)

Ok, I have new weirdness to report. I swapped the chips one by one into the Vader console to test them and both longer chips had issues. I put the original chipset back in the Vader and it no longer works, made sure the chips we're in the right spot etc. So I try putting the Vader chips in the heavy sixer and it now works but has no sound.

The main filter cap is failing/has failed if you're getting a loud hum. Try paralleling another cap of suitable voltage over it and at least 1000uf and see if the hum goes away. Also possible your voltage regulator isn't working right, double check that it's actually putting out clean 5V